Gastric dysplastic lesions in Helicobacter pylori-naïve stomach: Foveolar-type adenoma and intestinal-type dysplasia.

Reports of Helicobacter pylori (Hp)-naïve gastric neoplasm (HpNGN) cases have been rapidly increasing due to the recent increase in the Hp-naïve population in Japan. Most HpNGNs exhibit the gastric immunophenotype and a low malignant potential regardless of histological type. Especially, foveolar-type gastric adenoma (FGA) and intestinal-type gastric dysplasia (IGD) rarely progress to invasive carcinoma. FGA is a foveolar epithelial neoplasm that occurs in the fundic gland (oxyntic gland) mucosa and is classified as the flat type or raspberry type (FGA-RA). The flat type is a large, whitish flatly elevated lesion while FGA-RA is a small reddish polyp. Genomically, the flat type is characterized by APC and KRAS gene mutations and FGA-RA by a common single nucleotide variant in the KLF4 gene. This KLF4 single-nucleotide variant reportedly induces gastric foveolar epithelial tumorigenesis and activates both cell proliferation and apoptosis, leading to its slow-growing nature. IGD consists of an intestinalized epithelial dysplasia that develops in the pyloric gland mucosa, characterized as a superficial depressed lesion surrounded by raised mucosa showing a gastritis-like appearance. Immunohistochemically, it exhibits an intestinal or gastrointestinal phenotype and, frequently, p53 overexpression. Thus, IGD shows unique characteristics in HpNGNs and a potential multistep tumorigenic process.

Blocking cholesterol efflux mechanism is a potential target for antilymphoma therapy.

Cholesterol is an essential plasma membrane lipid for the maintenance of cellular homeostasis and cancer cell proliferation. Free cholesterol is harmful to cells; therefore, excessive free cholesterol must be quickly esterified by acetyl-coenzyme A:cholesterol acetyltransferase (ACAT) and exported by scavenger receptor class B member I (SR-BI) or ATP-binding cassette protein A1 from specific cells such as macrophage foam cells, which contain cholesteryl ester-derived vacuoles. Many vacuoles are present in the cytoplasm of Burkitt lymphoma cells. In this study, we observed that these vacuoles are often seen in high-grade lymphomas. Cell culture study using lymphoma cell lines found that esterified cholesterol is the main component of these vacuoles and the expression of cholesterol metabolism-related molecules was significantly upregulated in lymphoma cell lines, with SR-BI and ACAT inhibitors (BLT-1 and CI-976, respectively) impeding lymphoma cell proliferation. Cytoplasmic free cholesterol was increased by ACAT and SR-BI inhibitors, and the accumulation of free cholesterol induced lymphoma cell apoptosis by inducing endoplasmic reticulum stress. Furthermore, synergistic effects of SR-BI and ACAT inhibitors were observed in a preclinical study. Treatment with SR-BI inhibitor suppressed lymphoma progression in a tumor-bearing mouse model, whereas ACAT inhibitor did not. Therefore, SR-BI inhibitors are potential new antilymphoma therapeutics that target cholesterol metabolism.

[Successful treatment of myelodysplastic syndromes complicated by myeloid sarcoma with haploidentical allogeneic hematopoietic stem cell transplantation using post-transplant cyclophosphamide].

Using post-transplant cyclophosphamide (PTCy-haplo), haploidentical allogeneic hematopoietic stem cell transplantation has shown a surge in popularity in recent years. There are, however, only a few reports of PTCy-haplo being used to treat myelodysplastic syndromes (MDS) that have been complicated by myeloid sarcoma (MS). An immuno-suppressive therapy was given to a 25-year-old man who was diagnosed with low-risk MDS in September 2007. After an ileocecal ulcer biopsy that revealed MS in July 2019, a chromosomal analysis of the bone marrow cells in August 2019 revealed loss of chromosome 7, which is associated with poor prognosis. Because the patient lacked an HLA-matched sibling donor, he underwent PTCy-haplo in December 2019. On day 33, complete remission and donor chimerism was achieved. Ileocecal ulcer scarring was discovered by a colonoscopy on day 54. Grade I cutaneous acute graft-versus-host disease was discovered approximately on day 30 and treated with topical steroids. PTCy-haplo may be an effective treatment for MS.

[Warm autoimmune hemolytic anemia accompanied by metachronous double primary cancer].

In about half of the cases, autoimmune hemolytic anemia (AIHA) is secondary to an underlying disease, often due to paraneoplastic syndromes. Recently, the number of patients developing metachronous multiple primary malignant tumors (MPMTs) has been increasing due to the aging of the population and the longer survival times of those with malignant tumors. A 78-year-old woman was diagnosed with sigmoid colon cancer in May 2017 and with warm AIHA in October 2017. She received prednisolone for her warm AIHA treatment, which relieved her anemia symptoms. In January 2020, she had a warm AIHA relapse and received PSL again. In May 2020, she was diagnosed with peritonitis due to a small intestinal perforation and underwent laparoscopic partial resection of the small intestine. Subsequently, she was diagnosed with diffuse large B-cell lymphoma. It is important to consider the possibility of MPMTs and perform the appropriate examinations to determine whether malignant tumors are present in patients with a history of malignant tumors and a long history of AIHA relapse.

Incidence Patterns of Sequential or Composite Lymphoma: A Population-Based Cancer Registry Study.

The development of multiple histologic types of lymphoma in a single patient has been sporadically reported as sequential or composite lymphoma. However, the incidence pattern of such patients has been rarely evaluated in a large population-based setting. We investigated the incidence of sequential or composite lymphoma based on 11,174 lymphoma records from a population-based cancer registry between 1985-2012 in Nagasaki Prefecture, Japan. We identified 99 lymphoma records were of 49 independent patients other than relapse. The prevalence of the sequential or composite lymphomas in a single patient was 0.44% (95% confidence interval [95% CI], 0.32-0.56%) without sex difference. Among the 49 patients, five (10.2%) were composite/discordant lymphoma. The most frequent "composite lymphoma" was a combination of diffuse large B-cell lymphomas (DLBCL) and adult T-cell leukemia (n = 3). A case of "discordant lymphoma" was a combination of follicular lymphoma on spleen and Waldenström macroglobulinemia on bone marrow. The rest of the patients (n = 44, 89.8% of all composite lymphoma) were "sequential lymphoma" with various combination of lymphoma subtypes on different dates. The major combination of the sequential lymphoma was DLBCL after marginal zone lymphomas (n = 4). In the era of improved survival of lymphoma patients, hematologists should be aware of the development of additional lymphomas.

[Composite adult T-cell leukemia/lymphoma and Epstein-Barr virus-positive diffuse large B-cell lymphoma].

Human T-cell leukemia virus type I (HTLV-1) infection and adult T-cell leukemia-lymphoma (ATL) have been shown to cause immunodeficiency. However, only a few cases have been reported on the development of Epstein-Barr virus positive-diffuse large B-cell lymphoma (EBV-DLBCL) in HTLV-1 carriers or in patients with ATL. Here we report a case of a female HTLV-1 carrier who developed cytomegalovirus (CMV) retinitis. During the CMV retinitis treatment, she developed a liver tumor. The diagnosis of composite ATL and EBV-DLBCL was made by tumor biopsy. The patient also suffered from pulmonary cryptococcosis and invasive pulmonary aspergillosis at the time of chemotherapy initiation. She had repeated CMV antigenemia and bacterial sepsis during the course of chemotherapy, and she died of bacterial sepsis. HTLV-1 carriers who are complicated with opportunistic infections should be carefully observed not only for ATL development but also for the development of EBV-DLBCL and associated infectious complications.

[Enteropathy-associated T-cell lymphoma coexisting with composite lymphoma composed of DLBCL and PTCL].

The patient was a 73-year-old man diagnosed with low-grade B-cell lymphoma not otherwise specified based on a biopsy of the enlarged cervical lymph nodes. He remained untreated and was monitored during follow-up visits only. Progressive anemia developed after 5 years. Enteroscopy revealed stricture and ulcerative lesions involving the entire circumference of the middle section of the small intestine. Based on the biopsy results, he was diagnosed with enteropathy-associated T-cell lymphoma (EATL). Biopsy of an enlarged axillary lymph node simultaneously revealed Epstein-Barr virus-negative diffuse large B-cell lymphoma (DLBCL) and peripheral T-cell lymphoma not otherwise specified (PTCL, NOS) as well as rearrangement of immunoglobulin heavy-chain and T-cell receptor beta and gamma chain genes. These findings suggested that the axillary lymph node contained composite lymphoma comprising DLBCL and PTCL and that EATL represented a discordant lymphoma. The present case emphasizes the importance of re-biopsy and genetic analysis following an atypical clinical course.

[Gingival squamous cell carcinoma diagnosed on the occasion of osteonecrosis of the jaw in a patient with chronic GVHD].

A 44-year-old male was diagnosed with acute myeloid leukemia with a complex karyotype. He underwent bone marrow transplantation using an HLA 6/6 antigen-matched sibling donor, but developed chronic graft-versus-host disease (cGVHD) with skin erythema and oral and esophageal lichen planus changes. Treatment with a combination of prednisolone and cyclosporine was initiated on day 646 after transplantation, but oral symptoms persisted. The patient developed bilateral osteonecrosis of the lower jaw after extraction of the lower left and right molars on days 2,861 and 3,339, respectively. As the disease gradually progressed, segmental mandibular osteotomy was performed. Biopsy specimens demonstrated proliferation of squamous epithelial carcinoma cells in the bilateral gingiva and lower jaw bone, which confirmed the diagnosis of bilateral gingival squamous cell carcinoma. Thus, gingival squamous cell carcinoma should be considered as a differential diagnosis in post-transplant patients with refractory osteonecrosis of the jaw during the course of cGVHD.

Expression of programmed cell death ligand 1 is associated with poor overall survival in patients with diffuse large B-cell lymphoma.

Programmed cell death ligand 1 (PD-L1) is expressed on both select diffuse large B-cell lymphoma (DLBCL) tumor cells and on tumor-infiltrating nonmalignant cells. The programmed cell death 1 (PD-1)/PD-L1 pathway inhibits host antitumor responses; however, little is known about how this pathway functions in the tumor microenvironment. The aim of this study was to determine the clinicopathological impact of PD-L1(+) DLBCL. We performed PD-L1/PAX5 double immunostaining in 1253 DLBCL biopsy samples and established a new definition of PD-L1(+) DLBCL. We also defined the criteria for microenvironmental PD-L1(+) (mPD-L1(+)) DLBCL (ie, PD-L1(-) DLBCL in which PD-L1(+) nonmalignant cells are abundant in the tumor microenvironment). Of the 273 patients whose clinical information was available, quantitative analysis of PD-1(+) tumor-infiltrating lymphocytes (TILs) was performed. The prevalence rates of PD-L1(+) and mPD-L1(+) DLBCL were 11% and 15.3%, respectively. Both PD-L1(+) and mPD-L1(+) DLBCL were significantly associated with non-germinal center B-cell (GCB) type and Epstein-Barr virus positivity. The number of PD-1(+) TILs was significantly higher in GCB-type tumors and lower in mPD-L1(-) and PD-L1(+) DLBCL. Patients with PD-L1(+) DLBCL had inferior overall survival (OS) compared with that in patients with PD-L1(-) DLBCL (P = .0009). In contrast, there was no significant difference in OS between mPD-L1(+) and mPD-L1(-) DLBCL (P = .31). The expression of PD-L1 maintained prognostic value for OS in multivariate analysis (P = .0323). This is the first report describing the clinicopathological features and outcomes of PD-L1(+) DLBCL. Immunotherapy targeting the PD-1/PD-L1 pathway should be considered in this distinct DLBCL subgroup.

Analysis of the BRAFV600E mutation in 19 cases of Langerhans cell histiocytosis in Japan.

Langerhans cell histiocytosis (LCH) is a rare disease characterized by clonal proliferation of CD1a- and CD207 (langerin)-positive dendritic cells. Mutated BRAF (p.V600E) is observed in histiocyte-related diseases and dendritic cell-related diseases, including LCH. BRAFV600E is observed in some LCH cases and is thought to be involved in maintaining MAPK activation. We retrospectively analyzed BRAFV600E in 19 patients diagnosed with LCH. In our study, direct sequencing for exon 15, a mutation hotspot, demonstrated that 4 out of the 19 patients (21%) harbored a GTG > GAG (valine > glutamic acid) base substitution, which encodes BRAFV600E. The clinical impact of BRAFV600E in such diseases is unclear. The frequency of BRAFV600E in our LCH patients from Japan was lower than that reported in the United States and in Germany. However, reports from Asia tend to show a lower rate of the BRAFV600E mutation. These results imply the possibility of different genetic backgrounds in the pathogenesis of LCH across various ethnicities. We also performed an immunohistochemical analysis to detect BRAFV600E using the mutation-specific monoclonal antibody. However, immunohistochemical analysis failed to detect any mutated protein in any of the 4 BRAFV600E-positive cases. This implies that at present, BRAFV600E should be assessed by direct sequencing. Copyright © 2016 John Wiley & Sons, Ltd.

CCR4 frameshift mutation identifies a distinct group of adult T cell leukaemia/lymphoma with poor prognosis.

Adult T cell leukaemia/lymphoma (ATLL) is an intractable T cell neoplasm caused by human T cell leukaemia virus type 1. Next-generation sequencing-based comprehensive mutation studies have revealed recurrent somatic CCR4 mutations in ATLL, although clinicopathological findings associated with CCR4 mutations remain to be delineated. In the current study, 184 cases of peripheral T cell lymphoma, including 113 cases of ATLL, were subjected to CCR4 mutation analysis. This sequence analysis identified mutations in 27% (30/113) of cases of ATLL and 9% (4/44) of cases of peripheral T cell lymphoma not otherwise specified. Identified mutations included nonsense (NS) and frameshift (FS) mutations. No significant differences in clinicopathological findings were observed between ATLL cases stratified by presence of CCR4 mutation. All ATLL cases with CCR4 mutations exhibited cell-surface CCR4 positivity. Semi-quantitative CCR4 protein analysis of immunohistochemical sections revealed higher CCR4 expression in cases with NS mutations of CCR4 than in cases with wild-type (WT) CCR4. Furthermore, among ATLL cases, FS mutation was significantly associated with a poor prognosis, compared with NS mutation and WT CCR4. These results suggest that CCR4 mutation is an important determinant of the clinical course in ATLL cases, and that NS and FS mutations of CCR4 behave differently with respect to ATLL pathophysiology.

Internal exposure to neutron-activated 56Mn dioxide powder in Wistar rats-Part 2: pathological effects.

To fully understand the radiation effects of the atomic bombing of Hiroshima and Nagasaki among the survivors, radiation from neutron-induced radioisotopes in soil and other materials should be considered in addition to the initial radiation directly received from the bombs. This might be important for evaluating the radiation risks to the people who moved to these cities soon after the detonations and probably inhaled activated radioactive "dust." Manganese-56 is known to be one of the dominant radioisotopes produced in soil by neutrons. Due to its short physical half-life, 56Mn emits residual radiation during the first hours after explosion. Hence, the biological effects of internal exposure of Wistar rats to 56Mn were investigated in the present study. MnO2 powder was activated by a neutron beam to produce radioactive 56Mn. Rats were divided into four groups: those exposed to 56Mn, to non-radioactive Mn, to 60Co γ rays (2 Gy, whole body), and those not exposed to any additional radiation (control). On days 3, 14, and 60 after exposure, the animals were killed and major organs were dissected and subjected to histopathological analysis. As described in more detail by an accompanying publication, the highest internal radiation dose was observed in the digestive system of the rats, followed by the lungs. It was found that the number of mitotic cells increased in the small intestine on day 3 after 56Mn and 60Co exposure, and this change persisted only in 56Mn-exposed animals. Lung tissue was severely damaged only by exposure to 56Mn, despite a rather low radiation dose (less than 0.1 Gy). These data suggest that internal exposure to 56Mn has a significant biological impact on the lungs and small intestine.

Multicentric Castleman disease mimicking IgG4-related disease: A case report.

A 50-year-old woman was referred to our hospital for shoulder joint stiffness. She had a history of polyclonal hypergammaglobulinemia and an elevated C-reactive protein level. Her laboratory data revealed an elevated serum immunoglobulin G4 (IgG4) level, hypergammaglobulinemia, and rheumatoid factor positivity in the absence of anticyclic citrullinated peptide antibody. [18F]-Fluorodeoxyglucose positron emission tomography showed significant [18F]-fluorodeoxyglucose uptake in multiple lymph nodes (axillary, hilar, para-aortic, and inguinal). Biopsy of the inguinal lymph node showed expansion of the interfollicular areas by heavily infiltrating plasma cells, consistent with multicentric Castleman disease (MCD). Immunohistochemical analysis revealed a 37.3% IgG4-positive:IgG-positive plasma cell ratio, indicating overlapping IgG4-related disease. However, serological cytokine analysis revealed elevated levels of interleukin-6 (9.3 pg/ml) and vascular endothelial growth factor (VEGF) (1210 pg/ml), which are compatible with MCD. Corticosteroid treatment resolved the serological and imaging abnormalities. IgG4-related disease can mimic MCD, and it is crucial to distinguish between these two diseases. Serum interleukin-6 and VEGF levels may help to discriminate MCD from IgG4-related disease.

Endothelin B receptor expression in malignant gliomas: the perivascular immune escape mechanism of gliomas.

In order to clarify the role of endothelin B receptors (ETBRs) in gliomas, we analyzed cell cultures and surgical specimens of gliomas using RT-PCR and immunohistochemistry. RT-PCR measured the absolute expression of ETBR mRNA in twelve samples, which included gliomas that were classified using the World Health Organization (WHO) classification system Grade I-IV, as well as two glioblastoma cell lines (CCF-STTG1 and U87-MG). Using immunohistochemistry, 77 glioma specimens were evaluated for their expression of ETBR and infiltrating T lymphocytes, including an analysis of cytotoxic T cells (CTLs) and regulatory T lymphocytes (Tregs). The number of ETBR-positive vessels in the glioblastomas (Grade IV) was significantly higher than in other grades of gliomas (comparisons to Grade IV, Grade I: p = 0.0323, Grade II: p = 0.0009, Grade III: p = 0.0273). The ETBR expression rate (defined as the number of ETBR-positive blood vessels divided by the total number of blood vessels) in the glioblastomas was higher than the ETBR expression rate in the low-grade gliomas (compared to Grade IV, Grade I: p = 0.0132, Grade II: p = 0.0018, Grade III: p = 0.0745). In addition, the cases which had an ETBR expression rate of 50 % or higher exhibited fewer infiltrating CTLs and more infiltrating Tregs compared to the cases with an ETBR expression rate <50 % (CTLs: p = 0.0342; Tregs: p = 0.0175). Isocitrate dehydrogenase 1 (IDH-1) mutations were identified in 21 cases, but there was no correlation between ETBR expression and IDH-1 mutations for any WHO grade. These results suggest that ETBR expression during neo-angiogenesis may interfere with the homing of CTLs around the tumor and be involved in the immune escape mechanism of gliomas.

Role of tumor-associated macrophages in hematological malignancies.

The tumor microenvironment consists of many non-tumor cells such as leukocytes, endothelial cells, and fibroblasts, and phenotypic changes in a tumor microenvironment are believed to be involved in tumor progression and resistance to anticancer treatments. In hematological malignancies, tumor-associated macrophages (TAMs) that have infiltrated lymphoma or leukemia tissues may be involved in tumor progression, and many researchers have studied phenotypic changes in TAMs. This review article summarizes the publications related to TAMs in hematological malignancies, with an emphasis on CD163(+) protumoral TAMs, which seem to be associated with disease progression. Cell-cell interactions between protumoral TAMs and lymphoma or leukemia cells may play an important role in lymphoma or leukemia microenvironments. Although detailed molecular mechanisms of these cell-cell interactions have not yet been clarified, phenotypic characterization of TAMs is thought to be a useful approach for evaluating clinical prognosis. In addition, targeting TAMs may be a new strategy for treating malignant hematological diseases.

Clinicopathological features of double-hit B-cell lymphomas with MYC and BCL2, BCL6 or CCND1 rearrangements.

Double-hit (DH) lymphomas are B-cell lymphomas characterized by chromosomal rearrangements, specifically of MYC and either BCL2, BCL6 or CCND1. We reviewed 22 cases of DH lymphomas. BCL2/MYC DH lymphomas constituted the majority of these DH lymphomas (17 cases; 77%), followed by BCL6/MYC (2 cases; 9%) lymphomas. Assessing morphological features using the 2008 World Health Organization classification system, 15 cases (68%) were determined to be B-cell lymphoma, unclassifiable with features intermediate between diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma (BCLU) (10 cases; 45%), or as DLBCL (5 cases; 23%), and 2 cases (9%) were classified as morphologically untransformed follicular lymphoma. Burkitt lymphoma was rare (1 case; 5%) among DH lymphomas. Nineteen cases were treated with R-CHOP or a high dose chemotherapy regimen. After a median follow-up of 11 months, 7 patients had died, and the 1-year survival rate was 62.5%. High dose chemotherapy did not improve the outcome. We suggest that screening of genetic variations to detect DH lymphomas is required in diagnosing all lymphomas, even those determined morphologically to be follicular lymphoma.

Low incidence of MYC/BCL2 double-hit in Burkitt lymphoma.

Translocations involving MYC are highly characteristic for Burkitt lymphoma (BL). BCL2 expression has also been found previously in about 10 to 20% of BL cases, and BCL2 translocation is a major mechanism for the deregulation of BCL2 expression in non-Hodgkin lymphomas. However, we know little about the incidence of MYC/BCL2 double-hit (DH) in BL. We examined BL cases to determine how frequently they contained BCL2 translocations in combination with MYC translocations using fluorescence in situ hybridization. We also determined the effect of BCL2 expression on clinical outcomes of BL. BCL2 translocations were detected in 3.5% (2/57 cases) of the cases, and BCL2 expression was detected in 33%. Two cases with BCL2 translocation also showed BCL2 expression. The incidence of BCL2 expression was significantly higher in patients 16 years of age and older (46%) than in patients under 16 years of age (6%). Among patients 16 years of age and older, we did not detect significant differences in overall survival with respect to BCL2 expression status. In conclusion, BCL2 translocation is a rare cytogenetic abnormality in BL, and BL probably accounts for only a small fraction of MYC/BCL2 DH lymphomas. BCL2 expression in BL is probably not associated with BCL2 translocations.

Activated janus kinase 3 expression not by activating mutations identified in natural killer/T-cell lymphoma.

Janus Kinase 3 (JAK3) is a non-receptor tyrosine kinase, predominantly expressed in hematopoietic cells, that plays an essential role in hematopoiesis during T cell development. JAK3 somatic-activating mutations were identified in extranodal natural killer/T cell lymphomas (ENKTL) in recent cases in Singapore. We hypothesized these mutations might play an important role in the pathogenesis of T and NK cell neoplasms in other areas of the world. We performed JAK3 exon13 sequencing for different types of T and NK cell neoplasms including ENKTL (59 cases total). We identified four mutations in three (5.0%) cases. All of the mutations were from ENKTL cases (15.8%). Among the four newly found mutations, three are silent mutations and one introduces a stop codon, which was not an activating mutation as in the cases in Singapore. We detected four (30.8%) cases positive for phosphorylated JAK3 expression among 13 NKTCL cases when we performed JAK3 (phospho Y785) immunostaining on sections of ENKTL samples. It seems that phosphorylated JAK3 expression does not necessarily harbor exon 13 mutations. The mechanism responsible for activating expression of the gene will be a topic for further research.

CD5-positive follicular lymphoma characterized by CD25, MUM1, low frequency of t(14;18) and poor prognosis.

CD5-positive follicular lymphoma (FL), although rare, has been described in a number of case reports. However, a statistically valid, clinicopathological comparison between CD5-positive FL and CD5-negative FL has never been performed because of its rarity. We statistically compared clinicopathological characteristics of 22 cases of CD5-positive FL, diagnosed by immunohistochemistry, flow cytometry and morphological findings, with those of 62 cases of FL without CD5 expression (control cases). CD5-positive FL patients showed a higher tendency of peripheral blood involvement (P = 0.076) and a higher frequency of CD25 expression (P = 0.0004) and MUM1 protein expression (P = 0.0008), and a lower frequency of t(14;18)(q32;q21) (P = 0.017). The overall survival (OS) curve of CD5-positive FL was significantly worse than that of control cases (P = 0.0266), although progression-free survival curves did not show a significant difference (P = 0.7899). Moreover, CD5 expression was shown to be an independent poor prognostic factor for OS in both univariate analysis [Hazard Ratio (HR), 3.63; P = 0.0464] and multivariate analysis (HR, 57.16; P = 0.0001). CD5-positive FL showed different clinicopathological characteristics from FL lacking CD5 expression. These results suggest that CD5-positive FL should be considered a different type of FL, and its clinicopathological management should be conducted differently.

A Case Report of Carcinoid With Teratoma Arising From the Renal Hilum.

Teratoma is a germ cell tumor composed of 2 or 3 germ cell layers, and it can occur in various parts of the human body. However, teratomas of the renal hilum are particularly rare, and those complicated by carcinoids are even more uncommon. Herein, we report the example of an asymptomatic 49-year-old woman in whom a tumor in the right renal hilum was unexpectedly discovered on imaging. Histological examination revealed a carcinoid tumor arising from a simple cyst composed of teratomatous tissue. Although the tumor was located in the renal hilum and touched the renal parenchyma, it appeared independent of the kidney and urinary tract. This report highlights the rare occurrence of teratomas with carcinoids and provides insights into their origins.